msm: Add bindings for memblock_reserve memory

Under some circumstances, drivers may wish to have a region of
memory set aside with memblock_reserved instead of memblock_remove.
Add bindings for this reservation.

Change-Id: I41f4eeebf2f1a38374a7c8a0b65f6907d6e38faa
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>